This S3 generic is used for accessing the underlying Java Virtual Machine
(JVM) Spark objects associated with R objects. These objects act as
references to Spark objects living in the JVM. Methods on these objects
can be called with the invoke family of functions.
spark_jobj(x, ...)An R object containing, or wrapping, a spark_jobj.
Optional arguments; currently unused.
invoke, for calling methods on Java object references.